The goal of the research herein proposed is to develop a microcarrier - bioreactor - cell culture-based protocol that enables the rapid, efficient, low cost production of human influenza vaccine. Currently, virtually all human influenza virus vaccine is produced in embryonated eggs. The Federal government and the World Health Organization are actively seeking alternative cell culture approaches to flu vaccine production since there are several problems with the egg-derived vaccines. A cell culture-based protocol, with its potential to rapidly achieve large scale, would be invaluable in the case of an influenza pandemic. A new microcarrier substrate (Hillex), developed by SoloHill (under grant CA74595) has been shown to support attachment and growth of a variety of low adhesive cells in sera-free media and shows promise for this application. To achieve this research goal, the following two specific aims will be performed. Specific Aim I. To demonstrate feasibility for growing two different cell types (Vero and MDCK) on Hillex microcarriers and identify critical cell culture variables that will provide high cell yields on this substrate under serum-free conditions. Specific Aim II. To demonstrate influenza virus production on Vero and MDCK cells maintained on Hillex microcarriers (others have demonstrated that either Vero or MDCK cells can feasibly be used to propagate human influenza virus) under optimized bioreactor-type conditions. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE